Effect of different intracanal medicaments on the fracture resistance of the human root.

Background: The effect of different intracanal medicaments on root fracture resistance has not been thoroughly investigated in the short and long term. To assess the effect of calcium hydroxide (CH), CH combined with Chlorhexidine (CHX), double antibiotic paste (DAP), and simvastatin as intracanal medicaments on the fracture resistance of the human root. One hundred and twenty single-rooted mandibular premolars which were extracted for periodontal reasons were collected for this in vitro study. Materials and Methods: This was an in vitro study. All teeth were decoronated. Root canals were prepared by the Pro taper system, and %2.5 NaOCl was used for irrigation. The smear layer was removed using %5.25 NaOCl and 17% ethylenediaminetetraacetic acid each for 3 min. The samples were randomly divided into five groups based on the medicament: (1) CH (2) CH + CHX (3) Simvastatin (4) DAP (5) Control group. All specimens in each group were incubated for 1 week (Subgroup A) and 1 month (Subgroup B). Then, medicaments were removed and filled with gutta-percha and AH26 sealer. All samples were tested for fracture resistance. The data were statistically evaluated with the SPSS software 17. ANOVA and Mann-Whitney U and Wilcoxon tests were used for the analysis of the data. P = 0.05 was considered statistically significant. Results: Although CH and CH + CHX increased the fracture resistance in a 1-week period, there was no significant difference between the groups after 1 month. Conclusion: Under the limitations of this study, CH and CH + CHX, DAP and simvastatin do not have a negative effect on root fracture resistance when used as intracanal medicaments for <1 month.

Success Rate of Contemporary Regenerative Endodontic Therapy and the Expected Outcomes of the Endodontic Microsurgery: A Systematic Review and Meta-Analysis

ABSTRACT Objective: To examine the level of the accumulating success of the modern Resin-Based Endodontic Surgery (RES) and comparison with Endodontic Microsurgery (EMS) and finally offer a replacement at the predicted final results of EMS. Material and Methods: MEDLINE, PubMed, Cochrane Library, Embase, ISI, Google Scholar have been utilized as electronic databases for systematic literature until 2019. Therefore, Endnote X9, which can be provided in the market, has been applied to manage the electronic titles. Searches have been made with keywords "Endodontic Microsurgery OR EMS", "Resin-Based Endodontic Surgery OR RES", "Regenerative Endodontic Therapy", "Root-End Filling", "Root-End Surgery", "Periapical Surgery" and "Endodontics". Thus, this systematic review has been conducted concerningthe basic investigation of the PRISMA Statement-Preferred Reporting Items designed for the Meta-analyses and Systematic Reviews. Results: A total of RES =19 and EMS =31 with potential pertinent abstracts and topics were discovered in manual and electronic searches. Then, three articles for RES and four studies for EMS publications satisfied our inclusion criteria necessary for systematically reviewing the studies. The analysis showed the success rate for EMS as equal to 1.16 times the probability of the success rate for RES. Conclusion: Micro-surgical procedures superiorly achieved the predictable high success rate for the Root-end surgery compared to conventional methods.

The Comparison of Different Irrigation Systems to Remove Calcium Hydroxide from the Root Canal: A Systematic Review and Meta-Analysis

Abstract Objective: To examine the effect of a variety of irrigation systems on the removal of root canal Ca (OH)2 residues through meta-analysis and systematic review. Material and Methods: A search of relevant articles was systematically performed on databases of Medline, PubMed, Cochrane Library, Embase, ISI, and Google Scholar published from 2013 to 2019. Electronic title management was carried out by EndNote X9 software. Searches were based on the main keywords of "Irrigation Systems", "Calcium Hydroxide"," Root Canal", "Self-adjusting File OR SAF", "Conventional Irrigation", "EndoVac System", "Ultrasonic Irrigation" and "YAG Laser". Results: The studies investigated were found to lack any standardization concerning the irrigation method used or the measurement of outcomes; for instance, different studies used 5 or 10 mL of 2.5% NaOCl, or 5 mL of 5.25% NaOCl, or 0.5 mL, 3 mL and 10 mL of 17% EDTA. Conclusion: The effective techniques for the removal of root canal Ca(OH)2 were PUI, and SAF approaches.

Efficacy of Lasers Treatment of Exposed Pulps to Stimulate Healing: A Systematic Review and Meta-Analysis

Abstract Objective: The present systematic review and meta-analysis aimed at evaluating the efficacy of laser's treatment of exposed pulps to stimulate healing. Material and Methods: MEDLINE, PubMed, Cochrane Library, Embase, ISI, Google Scholar have been searched as the electronic databases for performing systematic literature between 2005 to 2019. Searches were performed with MESH terms. The quality of the studies included was assessed using the Critical Appraisal Skills Program checklist. For Data extraction, two reviewers blind and independently extracted data from the abstract and full text of the studies included. Moreover, the fixed-effect model's odds ratio for a 95% confidence interval (CI) was calculated. Random effects were used to deal with potential heterogeneity, and I2 showed heterogeneity. The meta-analysis and forest plots have been evaluated using the Comprehensive Meta-Analysis Stata. Results: Five studies (3 RCTs and 2 animal studies) were included in this study. The Odds Ratio was 1.90 (95% CI 1.39-2.42; p=0.00); there was a statistically significant difference between the laser and the control groups (p=0.00). Conclusion: The success rate of laser treatment for exposed pulps is higher than mineral trioxide aggregate, resin, calcium hydroxide and resin-modified glass-ionomer cement. The exact mechanism of this effect has not yet been determined; further research on lasers' impact on exposed pulps treatment is required.

Dental Pulpal Tissue Regeneration, Pulpal Vitality Testing, and Healing of Apical Lesions Following Stem Cell Transplant: A Systematic Review and Meta-Analysis

Abstract Objective: To analyze data obtained from animal and human studies using stem cells. Material and Methods: Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed, Cochrane Library, Embase, Information Sciences Institute (ISI), as well as Google Scholar were utilized and searched as available electronic databases to perform a systematic literature review of articles published between 2010 and 2019. The Endnote X9 for Windows was also employed to manage electronic titles and abstracts of the selected studies. Searches were conducted using keywords of "pulpal OR pulpal tissue OR pulpal vitality", "regeneration", "apical healing", "stem cells OR progenitor cells", and "mediated pulpal tissue". Consequently, 189 titles and abstracts endowed with potential relevance were discovered based on searches into manual and electronic sources. Ultimately, a total of six articles met the inclusion criteria in the present systematic review and meta-analysis. Results: Out of the six articles identified and selected, five studies were categorized as animal experiments and one article was nominated as a human clinical trial. The greatest bias risks were accordingly observed in the majority of animal examinations, but articles related to humans revealed decreased risks of bias, while the human clinical trial showed some concerns. Conclusion: Promising parameters testing functional pulp regeneration could be represented through stem cell transplants.

The effect of photodynamic therapy and polymer solution containing nano-particles of Ag /ZnO on push-out bond strength of the sealers AH-Plus and MTA Fillapex.

BACKGROUND: The aim of this in vitrostudy was to examine and compare the effect of photodynamic therapy and solution containing nano particles Ag/ZnO on adhesion of endodontic sealers to dentinal walls of human root canal. MATERIAL AND METHODS: Ninty single-rooted human teeth were selected and their clinical crown was cut from the cemento-enamel junction zone. Canals were prepared by RaCe rotary system and the smear layer was removed using 17% EDTA and 5.25% NaOCl. Samples were randomly divided into two groups of AH Plus and MTA Fillapex based on the sealer type and each group based on antimicrobial method was divided into two sub-groups of photodynamic therapy and polymer containing nano particles of Ag / ZnO and a control sub-group (N = 15). After obturation of canals with gutta-percha and sealers mentioned, the samples were incubated for a week at a humidity of 95% and 37°C and then 2mm thick discs were prepared from the middle region of roots for Push-out test. The maximum failure force was recorded in newton and converted to MPa. Then, 3 random specimens of each subgroup were evaluated by scanning electron microscopy. Statistical analysis was performed by Two way ANOVA and (P<0.05) was considered significant. RESULTS: The highest (4.84 ± 1.63) and lowest (0.16 ± 0.075) push-out bond strength values were obtained in (AH Plus-PDT) and (MTA Fillapex-Ag/ZnO) respectively. Independent of antimicrobial method, AH Plus bond strength was significantly higher than the MTA Fillapex (p<0.001). For both sealers, PDT increased the bond strength significantly (p<0.001). CONCLUSIONS: Photodynamic therapy has a positive effect on the bond strength of AH Plus and MTA Fillapex sealers. Key words:AH Plus, MTA Fillapex, Nano particles, Photodynamic therapy, Push-out.

Comparison of the Penetration Depth of Conventional and Nano-Particle Calcium Hydroxide into Dentinal Tubules.

INTRODUCTION: The aim of this in vitro study was to evaluate and compare the penetration depth of conventional (CH) and nano-particle calcium hydroxide (NCH) into dentinal tubules. METHODS AND MATERIALS: Ninety human single-rooted teeth were instrumented by RaCe rotary system and after chemomechanical preparation were randomly divided in two equal groups (n=45). In the first group conventional CH and in the other NCH was used as intracanal medicament. After 2 weeks of incubation all roots were intentionally split at longitudinal axis and prepared for scanning electron microscope (SEM) observation. Three zones of each root, coronal, middle and apical were examined under SEM and the maximum penetration depth of the dressing material into dentinal tubules was recorded for each zone. Data were analyzed using the independent sample t test and the level of significance was set at 0.05. RESULTS: In all of the three zones, NCH group had greater penetration depth than CH (P<0.001). In both groups the penetration depth increased from the apical section to the coronal. CONCLUSION: The depth of penetration of nano-particle calcium hydroxide into the dentinal tubules was significantly higher than that of conventional calcium hydroxide. The lowest penetration depth was observed in apical zone in both groups.

Immunohistochemical evaluation of myofibroblast density in odontogenic cysts and tumors.

Background. The aim of this study was to investigate myofibroblast (MF) density in a broad spectrum of odontogenic cysts and tumors and the relation between the density of MFs and the clinical behavior of these lesions. Methods. A total of 105 cases of odontogenic lesions, including unicystic ameloblastoma (UAM), solid ameloblastoma (SA), odontogenic keratocyst (OKC), dentigerous cyst (DC), radicular cyst (RC) (15 for each category), and odontogenic myxoma (OM), adenomatoid odontogenic tumor (AOT), calcifying odontogenic cyst (COC) (10 for each category), were immunohistochemically stained with anti-α-smooth muscle actin antibody. The mean percentage of positive cells in 10 high-power fields was considered as MF density for each case. Results. A statistically significant difference was observed in the mean scores between the study groups (P < 0.001). The intensity of MFs was significantly higher in odontogenic tumors compared to odontogenic cysts (P < 0.001). There was no statistically significant difference between odontogenic tumors, except between UAM and OM (P = 0.041). The difference between OKC and odontogenic tumors was not statistically significant (P > 0.05). The number of MFs was significantly higher in OKC and lower in COC compared to other odontogenic cysts (P = 0.007 and P = 0.045, respectively). Conclusion. The results of the present study suggest a role for MFs in the aggressive behavior of odontogenic lesions. MFs may represent an important target of therapy, especially for aggressive odontogenic lesions. Our findings support the classification of OKC in the category of odontogenic tumors.